RFR: 8222210: JFXPanel popups open at wrong coordinates when using multiple hidpi monitors [v2]

[Kevin Rushforth]

On Fri, 28 Oct 2022 06:42:21 GMT, Johan Vos <jvos at openjdk.org> wrote:

>> The root problem is actually broader than stated in the JBS issue. This PR now translates screencoordinates from absolute coordinates into coordinates that take the platformScale into account. 
>> The whole process is complicated by the fact that throughout our code, we use e.g. `x` and `y` without clearly stating if those are absolute, logical, screen or rendering coordinates. 
>> I believe the most consistent approach is to have the different entry points (e.g. a Glass Window or a JFXPanel) to deal with platformScale before passing screen coordinates. This is already done in the Glass approach, and this PR does the same in JFXPanel. That means some code is duplicated, but since this is only about 12 lines, and said code lives in 2 different modules, I think it's not worth the hassle of moving that into e.g. the base module.
>
> Johan Vos has updated the pull request incrementally with one additional commit since the last revision:
> 
>   address reviewer comments
>   Fix detection on screen, based on awtScale factors

I think this looks basically correct, although I did leave a couple questions / comments inline. I'll test it next week.

modules/javafx.swing/src/main/java/javafx/embed/swing/JFXPanel.java line 387:

> 385:     private Dimension2D convertSwingToFxPixel(GraphicsConfiguration g, float wx, float wy) {
> 386:         float newx, newy;
> 387:         Screen screen = findScreen(getGraphicsConfiguration());

Did you mean to use the passed in graphics config, `g`? If not, you might remove the `g` parameter, since it is otherwise unused.

modules/javafx.swing/src/main/java/javafx/embed/swing/JFXPanel.java line 400:

> 398:             float py = screen.getPlatformY();
> 399:             newx = sx + (wx - px) * awtScaleX / pScaleX;
> 400:             newy = sy + (wy - py) * awtScaleY / pScaleY;

`px` and `py` are already (scaled) "FX" coordinates, so I'm not sure AWT scale should be applied to that. I might be missing something here.

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PR: https://git.openjdk.org/jfx/pull/924